No. 6. DEPARTMENT OF AGRICULTURE. 689 



p]y a need of that element, if such need exists, as is very often the 

 case, notably with sandy soils. 



Carriers of Potash. — The cheapest carrier of potash for most po- 

 tato-growers is the muriate. It is a common impression that this 

 material alTects the quality of the tubers adversely, and the rather 

 more costly sulphate is advised. In my own fields I have made some 

 tests, selecting tubers from hills treated with the muriate, and other 

 tubers from hills on an adjoining plat untreated, and having them 

 cooked together under proper conditions. So far I have been unable 

 to detect the slightest injury to edible quality from use of potash in 

 the form of a muriate, and this has led to the study of Experiment 

 Station tests with the result that the character of soil or season ap- 

 T^ears to be a determining factor. There is less assurance of the 

 slig'htest injury to the quality of the potato from use of the muriate 

 than would be exj)ected from the importance that has been attached 

 to the matter by writers. It appears that in some soils quality ks 

 affected, at least, when the potash is not applied before the planting 

 so that the salt may be washed out by rains. In other soils there 

 are no ill results. It is a matter easy of test for the grower, as both 

 sulphate and muriate forms are on the market everywhere. Kainit, 

 a low-grade sulphate form, contains so big a percentage of salt that 

 it should be classed with the muriate in effect upon quality. 



In respect to effect upon yield, it is probable that the more costly 

 sulphate is the cheaper source of plant food for acid soils, while 

 the muriate is most satisfactory for all other soils. The Rhode Is- 

 land Station has arrived at this conclusion from the study of its own 

 results in comparison with those of other Stations. 



Ashes. — An application of hard-wood ashes usually has a favor- 

 able effect upon the yield of potatoes. As such ashes are rich in 

 potash, this effect is doubtless one cause of the very common belief 

 that potash is peculiarly a potato fertilizer. The truth is that ashes 

 exert an effect upon most crops wholly out of proportion to their 

 potash content, and therefore attributable to some other element 

 or elements in the ashes. It is known that the lime in ashes is in an 

 especially effective form, exerting much influence upon the soil. 

 While, as has been stated, hard-wood ashes affect yields favorably, 

 they promote diseases that roughen the skin of the potato, and their 

 use is not advised except on acid soils. In some soils they also have 

 an unfavorable effect upon the texture of the land. 



Coal ashes contain practically no fertilizing qualities, but I have 

 found that it pays to draw and spread the home supply on the more 

 clayey parts of the potato land for its improvement in physical con- 

 dition. They should be spread before the harrow% and worked into 

 The surface soil. 



44—6—1902 



